Lubricant composition



oils, alcohols,

Patented Sept. 14, 1943 LUBRICANT COMPOSITION Henry G. Berger, Woodbury,and Francis M.

Sager, Pitman, N. J., assignors to Socony-Vaeuum- Oil Company,Incorporated, New York, N. Y., a corporation of New York No Drawing.Application May 22, 1941, 8121181 N0. 394,616

3 Claims.

This invention has to do with lubricant compositions and is moreparticularly concerned with lubricants adapted for use under extremepressure conditions such as are encountered between relatively movingengaged surfaces in various types of modern machinery, such as thehypoid gears in motor vehicles.

The present invention contemplates a lubricant comprised of a suitablecarrying medium such as mineral oil which may or may not have inherentlubricant properties and a dissolved or suspended ingredient which willimpart to the composition the property of lubricating metal surfacesengaged under extreme pressures. The carrying medium is preferably amaterial either in the nature of a liquid or a grease, which preferablyhas lubricant properties. Viscous mineral oils are representative ofsuch a preferred carrying medium. It is to be understood, however, thatthe invention is not limited to this particular type of carrying mediumbut contemplates any medium of suitable volatility in which the extremepressure ingredient or "E. P. base can be dissolved, dispersed, oremulsified. Other typical carrying agents contemplated herein arerelatively non-viscous petroleum hydrocarbons such as kerosene, andfatty vegetable or animal esters, ethers, etc.

Among the various bases or ingredients which have heretofore beenproposed for the compounding of extreme pressure lubricants are organiccompounds containing chlorine and sulfur in chemical combination. Thenovel compounds or reaction products contemplated herein may beconsidered as falling roughly into that general class of compounds, butthey are characterized by the fact that the active constituents(chlorine and sulfur) predominate over the organic (carbon) constituent.The materials contemplated for use in compounding the novel lubricantcompositions described herein are obtained by reactingperchloromethylmercaptan (CI3C.SC'1) with elementary sulfur. Thisreaction gives rise to a number of reaction products. believed to be acomplex mixture of trichlormethyl polysulfldes with unreacted (7130.801,byproduct ScClz, and various decomposition products of Cl3.SCl and thepolysulfides, such as CCh, CSClz, S, CS: and SClz. For this reason thematerial contemplated herein as an addition agent for lubricantcompositions much be characterized as a reaction product rather than adefinite chemical compound, but neglecting the concurrent reactionswhich give rise to decomposition products it is believed that thereaction can be roughly represented as follows:

The general procedure for obtaining the reaction products contemplatedherein involves the reaction of from 2 to 6 parts ofperchloromethylmercaptan with 1 part of elementary sulfur at a reactiontemperature between and C. This is calculated to give from 6 to 2,respectively, as the value of :r in the formula (ChCMSz, whichrepresents the average composition of the polysulfldes in the mixture.

Since some of the constituents in the reaction product (such as theS201: by-product, unreacted C13C.SC] and decomposition products ofClsC.SCl) are of relatively high volatility, it is desirable to top thecrude reaction product for most satisfactory results. Thus, the crudereaction mass may, if desired, be topped at about 100 C. pot temperatureat 2 mm. Hg. to remove the more volatile constituents, including SzClzand unreacted ClaC.SCl.

As aforesaid, the principal object of this invention is the developmentof extreme pressure lubricant compositions and with that in mind ourinvention contemplates the use of any carrying agent wherein a minorproportion of reaction product herein described can be dissolved,dispersed or emulsified. We have discovered, however, that thesereaction products, when added to viscous mineral oils, are effective toimpart desirable properties other than increased load-carrying capacity.For example, reaction products of the class described, or fractionsthereof, may be used in viscous mineral oil fractions in amounts lessthan those normally desired for extreme pressure properties, to inhibitor retard the deleterious effects of oxidation on such oils as evidencedby reduction in acid formation in highly refined transformer oils andreduction in corrosion of alloy bearings in solventrefined motor oils.

Perchloromethylmercaptan, as indicated by the formula above, is achlorinated substituted sulfur chloride and can be prepared by thechlorination of carbon disulflde according to the method of Helfrich andReid (Jour. Amer. Chem. Soc. 43, 591 (1921)). For example, carbondisulfide containing about .4 per cent by weight of iodine waschlorinated in the absence of direct sunlight at a temperaturemaintained below 25 C. until the volume of the reaction mixture haddoubled. The crude product, which has been topped to remove carbontetrachloride and sulfur dichloridc, is predominantlyperchloromcthylmercaptun with some sulfur monochloride. This crudeproduct can be used in the preparation of the reaction productscontemplated herein, or it may be purified by fractionation.

As aforesaid, the addition agents contemplated herein are preferablyobtained by reacting from two to six parts of perchloromethylmercaptanwith one part of sulfur, and the reaction is best carried out atelevated temperatures of from about 145 to about 170 C. with the heatedreaction mixture under a reflux condenser. The product may befractionated and purified as hereinafter indicated or, if desired, afterinitial topping, it may be treated (as by water-washing) to destroytraces of sulfur chloride and further treated (as by dilution withpetroleum ether) to precipitate elementary sulfur, and then blended withthe oil or other carrying medium in the proportions desired for theparticular result to be accomplished.

Further details in procedures for preparing reaction products of thetype contemplated herein and indications as to their effectiveness asaddi- 'tion agents for lubricant compositions may be obtained from thefollowing examples:

Example I A reaction mixture consisting of 32 grams (1.0 atom) of sulfurand 203 grams (1.1 moles) of crude C13C.SC1 (steam-distilled but notfractionated) was heated under reflux to an initial pot temperature of110 C.; and after a small amount of low-boiling material was taken off,the temperature rose to 147 C. and was held at 146- 163" C. for a totalof 9 hours. The take-011 coniensed during these operations was only 8grams. On steam-treatment, only 8 grams of steam distillate wasobtained. A 5 per cent blend in lubricating oil of the nonvolatileproduct of this reaction tested 570+ pounds on the S. A. E. test machine(described in S. A. E. Journal 39, 23-4 (1936)), and in the Almen test(Proc. A. P. I., 1932, pages 118-130) this blend tested 30,000+ pounds.

The foregoing reaction product, which analyzed 50.5 per cent chlorineand 38.3 per cent sulfur, was distilled under vacuum (1 mm. Hg.) and 60per cent came over at 107-160 C., The other 40 per cent was leftundistilled. The distillate analyzed 57.1 per cent Cl and 35.3 per cents. Calculated values for his trichlormethyl tetrasulfide ((C13C) 284)are 58.4 per cent chlorine and 35.1 per cent sulfur.

Emample II A reaction mixture consisting of 48 grams (1.5 atoms) ofsulfur and 187 grams (1.0 mole) of perchlorornethylmercaptan (B. P.80-81 C./90 mm. Hg.) was heated under reflux for a total of about 11hours at a temperature of from 145 to 168 /2? C. Eighty-eight grams ofdistillate were then taken off below 92 C. at 7 mm. pressure anddiscarded. The residual material was I fractionally distilled to givethe following two this fraction in lubricating oil gave an S. A. E. testvalue of 365 pounds and an Almen test value of 26,000 pounds.

Example III A reaction mixture consisting of 48 grams (1.5

atoms) of sulfur and 186 grams of perchloromethylmercaptan was heatedunder reflux for a total of 13% hours at a temperature of from 139 to166 /2 C. In this run, as in the preceding runs, the temperature of themixture at refiux showed a characteristic sharp rise followed by agradual decline. Vapor loss was again negligible. below 135 C. pottemperature at mm. pressure was discarded. The residual material wasthen stirred with water, taken up inpetroleum ether, filtered andtopped. This product was fractionally distilled to give the followingtwo fractions:

(1) 53 grams of distillate boiling at 50-120 C.-

at 25 mm, pressure, which in 3 per cent blend in lubricating oil gave anS. A. E. test value of 350 pounds and an Almen test value of 30,000pounds.

(2) 43 grams of distillate boiling at -140 C. at 0.2 mm. pressure. Thisfraction in a 3 per cent blend in lubricating oil gave an S. A. E. testvalue of 540 pounds and an Almen test value of 30,000 pounds.

From the foregoing it will be seen that the crude product obtained bythe reaction of perchloromethylmercaptan and sulfur, together with thevarious products obtained by fractionating and refining such crudeproduct, are all effective extreme pressure agents, and it is to beunderstood that where the term reaction product is used herein, suchterm is intended to include the various fractions typified by thosedescribed in the examples either alone or in admixture with the otherproducts of reaction.

As aforesaid, the reaction products contemplated herein have also beendemonstrated to be effective to inhibit the deleterious effects ofoxidation on refined viscous petroleum oils of the type used aslubricants and dielectrics. For example, fraction 2 from Example IV wasblended in an amount of 0.25 per cent in a solvent-refined motor oil,and the blend and blank oil were subjected to a bubble test todemonstrate corrosiveness toward cadmium-silver bearing metals. Theblank showed a weight loss of 32 mg. in a G-gram bearing section, whilethe blend showed a loss of only 1 mg. on the same-sized section of thesame bearing. The fraction 1 from Example IV showed a. 4 mg. loss inbearing weight with a 0.25 per cent blend as against a 48 mg. loss forthe blank oil. Blends of a highly refined transformer oil containing 0.1per cent of these same fractions were subjected to a modified German tartest, and the following neutralization numbers (N. N.) were obtained:

Product added N. N.

None 25. 00 0.1% fraction 1, Example IV l. 2 0.1% fraction 2, Example IV0. 04

Seventy-six grams of distillate takenand when added for the sole purposeof inhibiting oxidation the amount will vary from .01 per cent to .50per cent. In general, therefore, as regards mineral oil compositions,our invention contemplates proportions of the reaction product rangingfrom 0.01 to 10.0 per cent.

It is to be understood that while we have herein described variousprocedures for obtaining and purifying the reaction productscontemplated herein, the invention is not limited to the details of suchprocedures but includes within its scope such changes and modificationsas fairly come within the spirit of the appended claims.

We claim:

1. A lubricant composition comprising a hydrocarbon lubricating oil andin admixture therewith a minor proportion of the product obtained byrefluxing from two to six parts of perchloromethylmercaptan with onepart of sulfur at a temperature of from 145' to 170 C.

2. A lubricant composition comprising a hydrocarbon lubricating oil andin admixture therewith a minor proportion of the product obtained byrefluxing from two to six parts of perchloromethylmercaptan with onepart of sulfur at a temperature of from 145 to 170 C., and then removingsulfur chloride and unreacted sulfur from the reaction product.

3. A lubricant composition comprising a hydrocarbon lubricating oil andin admixture therewith a minor proportion of from 0.01 per cent to 10.0per cent of the product obtained by refluxing from two to six parts ofperchioromethylmercaptan with one part of elementary sulfur at atemperature of from 145 C. to 170 C., and then removing sulfur chlorideand unreacted sulfur from the reaction product.

HENRY G, BERGER. FRANCIS M. SEGER.

